Torque wrench calibration

[ThunderSteve]

I've done that with a digital scale, and it worked fine for rough checks. Just pull at 90 degrees. For better accuracy or if you use it often, pro calibration might be worth it.

[blurredman]

[ThunderGuts]

Finally got around to doing some testing. The big Draper wrench “clicks” on a torque about 20% lower than the number dialled into it. My mid-range wrench which is a Halfords Advanced one was within 5%. What I find disconcerting is that implies the 180Nm I was striving for is probably closer to about 145Nm in reality but that felt ‘king tight so I think I’ll leave them as they are!
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TG.

[A100man]

[Ducked]

If you are really cheap you can calibrate a bungee for stretch and use it with any standard spanner. I did this using bicycle inner tube when I didn't have clearance for my torque wrench and it worked very well, so much so that I doubt I would buy a torque wrench now if I didn't already have one.

Described toward the sad end of this very long thread

https://tw.forumosa.com/t/damaged-spark-plug-hole-thread-chaser/228793/340

This would allow one to make a range of pull-O-meters accurate at different force levels, but I seldom use a torque wrench anyway so havn't bothered with that.trick

As a follow-up I got some really cheap (dressmakers?) tape measures which could be used to measure the stretch of the inner tube. Some are ratchetting so would record the maximum force applied, but since the cops got my car I havnt had reason to use them.